1# CI Scripts
2
3This directory contains scripts for each build step in each build stage.
4
5## Running a Stage Locally
6
7Be aware that the tests will be built and run in-place, so please run at your own risk.
8If the repository is not a fresh git clone, you might have to clean files from previous builds or test runs first.
9
10The ci needs to perform various sysadmin tasks such as installing packages or writing to the user's home directory.
11While it should be fine to run
12the ci system locally on your development box, the ci scripts can generally be assumed to have received less review and
13testing compared to other parts of the codebase. If you want to keep the work tree clean, you might want to run the ci
14system in a virtual machine with a Linux operating system of your choice.
15
16To allow for a wide range of tested environments, but also ensure reproducibility to some extent, the test stage
17requires `bash`, `docker`, and `python3` to be installed. To run on different architectures than the host `qemu` is also required. To install all requirements on Ubuntu, run
18
19```
20sudo apt install bash docker.io python3 qemu-user-static
21```
22
23For some sanitizer builds, the kernel's address-space layout randomization
24(ASLR) entropy can cause sanitizer shadow memory mappings to fail. When running
25the CI locally you may need to reduce that entropy by running:
26
27```
28sudo sysctl -w vm.mmap_rnd_bits=28
29```
30
31To run a test that requires emulating a CPU architecture different from the
32host, we may rely on the container environment recognizing foreign executables
33and automatically running them using `qemu`. The following sets us up to do so
34(also works for `podman`):
35
36```
37docker run --rm --privileged docker.io/multiarch/qemu-user-static --reset -p yes
38```
39
40It is recommended to run the CI system in a clean environment. The `env -i`
41command below ensures that *only* specified environment variables are propagated
42into the local CI.
43To run the test stage with a specific configuration:
44
45```
46env -i HOME="$HOME" PATH="$PATH" USER="$USER" FILE_ENV="./ci/test/00_setup_env_arm.sh" ./ci/test_run_all.sh
47```
48
49## Configurations
50
51The test files (`FILE_ENV`) are constructed to test a wide range of
52configurations, rather than a single pass/fail. This helps to catch build
53failures and logic errors that present on platforms other than the ones the
54author has tested.
55
56Some builders use the dependency-generator in `./depends`, rather than using
57the system package manager to install build dependencies. This guarantees that
58the tester is using the same versions as the release builds, which also use
59`./depends`.
60
61It is also possible to force a specific configuration without modifying the
62file. For example,
63
64```
65env -i HOME="$HOME" PATH="$PATH" USER="$USER" MAKEJOBS="-j1" FILE_ENV="./ci/test/00_setup_env_arm.sh" ./ci/test_run_all.sh
66```
67
68The files starting with `0n` (`n` greater than 0) are the scripts that are run
69in order.
70
71## Cache
72
73In order to avoid rebuilding all dependencies for each build, the binaries are
74cached and reused when possible. Changes in the dependency-generator will
75trigger cache-invalidation and rebuilds as necessary.
76
77## Configuring a repository for CI
78
79### Primary repository
80
81To configure the primary repository, follow these steps:
82
831. Register with [WarpBuild](https://www.warpbuild.com/) and purchase runners.
842. Install the WarpBuild GitHub app against the GitHub organization.
853. Enable organisation-level runners to be used in public repositories:
86   1. `Org settings -> Actions -> Runner Groups -> Default -> Allow public repos`
874. Permit the following actions to run:
88   1. actions/cache/restore@\*
89   1. actions/cache/save@\*
90   1. actions/github-script@\*
91   1. docker/setup-buildx-action@\*
92   1. warpbuilds/cache/restore@\*
93   1. warpbuilds/cache/save@\*
94
95### Forked repositories
96
97When used in a fork the CI will run on GitHub's free hosted runners by default.
98In this case, GitHub's cache size limitations may cause caches to be frequently evicted and missed, but the workflows will run (slowly).
99
100It is also possible to use your own WarpBuild Runners in your own fork by replacing the references to `bitcoin/bitcoin` in `../.github/workflows/ci.yml` with the name of your fork (e.g. `your-org/bitcoin`).
101NB that WarpBuild Runners only work at an organisation level, therefore in order to use your own WarpBuild Runners, *the fork must be within your own organisation*.
102